The long term objective of this research is to develop tissue engineering strategies for the understanding and treatment of craniofacial abnormalities. This proposal is both hypothesis and design driven. We will investigate tissue development of cells from mouse models of the craniofacial abnormality Apert syndrome. We hypothesize that mutant cells from the FGFR2 knock-in Apert mouse model developed by the co-Pi will develop tissue and respond to growth factors in a significantly different manner compared to normal cells when grown in monolayer or in three dimensional hydrogel scaffolds. Furthermore, we hypothesize that when the normal and mutant cells are cocultured in multilayered hydrogel scaffolds, proliferation, tissue development, and growth factor response will change. The design driven portion of the proposal will develop a clinically practical strategy for repair of craniofacial defects, in iatrogenic defects and in the disease mouse model, using cell encapsulation technologies developed by the lab. To test these hypotheses and design the repair system the following specific aims will be investigated: Specific aim 1. Investigate cell behavior and tissue development of cells isolated from FGFR2 knock-in mouse model of Apert Syndrome. Specifically this aim will address 1.) chondrogenesis and osteogenesis of cells from a Fgfr2+/S252W mouse model of Apert Syndrome, compared to cells from normal siblings and an immortalized, clonal mouse mesenchymal stem cell line. Cells from a.) the long bone and b.) the cranium will be evaluated in 2D monolayer and 3D hydrogel scaffolds in vitro. Specific aim 2. Investigate cell behavior and tissue development of mutant and normal cells in response to growth factors and co-culture. Specifically this aim will address 1.) response of mutant and normal cells to musculoskeletal-related growth factors in 2D and 3D hydrogel culture, and 2.) apply a novel 3D bilayered hydrogel system to coculture normal and mutant cells to determine the effects of coculture on cell behavior and tissue development of normal and mutant cells. Specific aim 3. Determine in vivo function of mutant and normal cells in craniofacial models. Specifically, tissue development in 1.) iatrogenic mouse cranial defects and 2.) congenital defects in Apert Syndrome will be evaluated using cells embedded in hydrogels. Normal and mutant mouse cell lines will be used in addition to a clonally-derived mouse mesenchymal stem cell line. Tissue development will be assessed by radiographic and histological analyses